# CVE-2024-42084: ftruncate: pass a signed offset

> A missing sign extension in the Linux kernel ftruncate syscall allows attackers to truncate files to unintended large sizes, potentially causing data loss.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Jul 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2024-42084, DEBIAN-CVE-2024-42084, GHSA-h3c9-8xwq-2j95, UBUNTU-CVE-2024-42084

## What is CVE-2024-42084?

CVE-2024-42084 is a medium-severity vulnerability in Linux kernel, published on 29 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ftruncate: pass a signed offset

The old ftruncate() syscall, using the 32-bit off_t misses a sign
extension when called in compat mode on 64-bit architectures.  As a
result, passing a negative length accidentally succeeds in truncating
to file size between 2GiB and 4GiB.

Changing the type of the compat syscall to the signed compat_off_t
changes the behavior so it instead returns -EINVAL.

The native entry point, the truncate() syscall and the corresponding
loff_t based variants are all correct already and do not suffer
from this mistake.

## Which versions are affected by CVE-2024-42084?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-42084?

Apply the vendor's patch.

## Is CVE-2024-42084 being exploited?

There is no known exploitation of CVE-2024-42084 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-42084 and fix it if it is affected.

What it is: CVE-2024-42084 is a medium-severity vulnerability in Linux kernel, published on 29 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-42084 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-42084/ (Markdown: https://insights.sbomify.com/CVE-2024-42084/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-42084
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-42084
- OSV: https://osv.dev/vulnerability/CVE-2024-42084

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-42084/
Summaries are generated and may contain mistakes; the official description above is the record.